A153726 Initial digit of Catalan number A000108(n).

1, 1, 2, 5, 1, 4, 1, 4, 1, 4, 1, 5, 2, 7, 2, 9, 3, 1, 4, 1, 6, 2, 9, 3, 1, 4, 1, 6, 2, 1, 3, 1, 5, 2, 8, 3, 1, 4, 1, 6, 2, 1, 3, 1, 5, 2, 8, 3, 1, 5, 1, 7, 2, 1, 4, 1, 6, 2, 1, 4, 1, 6, 2, 9, 3, 1, 5, 2, 8, 3, 1, 5, 2, 7, 3, 1, 4, 1, 7, 2, 1, 4, 1, 6, 2, 1

Offset: 0

Author

Omar E. Pol, Dec 30 2008

Keywords

• base
• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A000030, A008963, A077648, A152669.

Programs

Mathematica

First[IntegerDigits[#]]&/@CatalanNumber[Range[0,120]] (* Harvey P. Dale, Jan 20 2014 *)

Formula

a(n)=A000030(A000108(n)).

Extensions

More terms from Harvey P. Dale, Jan 20 2014